Extended base pair complementarity between U1 snRNA and the 5' splice site does not inhibit splicing in higher eukaryotes, but rather increases 5' splice site recognition.
Extended base pair complementarity between U1 snRNA and the 5' splice site does not inhibit splicing in higher eukaryotes, but rather increases 5' splice site recognition.
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DOI：
10.1093/nar/gki824
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发表时间：
2005
影响因子：
14.9
通讯作者：
Schaal H
中科院分区：
文献类型：
--
作者：
Freund M;Hicks MJ;Konermann C;Otte M;Hertel KJ;Schaal H
剪接体的形成是通过5′剪接位点和U1 snRNA之间形成RNA双链体识别5′剪接位点而启动的。我们之前已经证明，U1 snRNA和5′剪接位点之间的RNA双链体形成可以保护pre-mRNAs在剪接前不被降解。这个初始的RNA双链体必须被破坏，以暴露5′剪接位点序列与U6 snRNA进行碱基配对，并形成活性剪接体。在此，我们研究了U1 snRNA/5′剪接位点双链体的超稳定性是否会干扰人类细胞系或细胞核提取物中的剪接效率。与酿酒酵母中的观察不同，我们证明了扩展的U1 snRNA/5′剪接位点相互作用不会降低剪接效率，而是增加了5′剪接位点识别和外显子包含。然而，5′剪接位点与U1 snRNA的低互补性显著增加外显子跳跃和RNA降解。虽然剪接机制在人和酿酒酵母之间是保守的，但这些结果表明剪接体的激活存在明显差异。
Spliceosome formation is initiated by the recognition of the 5′ splice site through formation of an RNA duplex between the 5′ splice site and U1 snRNA. We have previously shown that RNA duplex formation between U1 snRNA and the 5′ splice site can protect pre-mRNAs from degradation prior to splicing. This initial RNA duplex must be disrupted to expose the 5′ splice site sequence for base pairing with U6 snRNA and to form the active spliceosome. Here, we investigated whether hyperstabilization of the U1 snRNA/5′ splice site duplex interferes with splicing efficiency in human cell lines or nuclear extracts. Unlike observations in Saccharomyces cerevisiae, we demonstrate that an extended U1 snRNA/5′ splice site interaction does not decrease splicing efficiency, but rather increases 5′ splice site recognition and exon inclusion. However, low complementarity of the 5′ splice site to U1 snRNA significantly increases exon skipping and RNA degradation. Although the splicing mechanisms are conserved between human and S.cerevisiae, these results demonstrate that distinct differences exist in the activation of the spliceosome.